1. Field of the Invention
The present invention relates to a process for producing glucose-1-phosphate making use of microorganisms.
2. Description of the Background Art
Glucose-1-phosphate (hereafter abbreviated as xe2x80x9cG-1-Pxe2x80x9d) is useful as a substrate for syntheses of drugs and saccharides.
G-1-P is mainly obtained by phosphorolysis of starch or dextrin with maltodextrin phospholylase (MDPase), and a process making use of MDPase derived from potato (Japanese Patent Publication No. 95942/1994) and the so-called enzymatic process using MDPase derived from microorganisms have been reported to date.
As examples of the enzymatic process using MDPase derived from microorganisms, have been reported a process using an enzyme derived from Escherichia coli (Enzyme Microb. Technol. 17, 140-146 (1995) and a process using an enzyme derived from Corynebacterium callunae (J. Carbohydrate Chem., 14,1017-1028 (1995)). More recently, processes for producing G-1-P making use of heat-stable MDPase derived from medium thermophilic bacteria and high thermophilic bacteria such as Bacillus stearothermophilus (Japanese Patent Application Laid-Open No. 14580/1998) and Thermus caldophilus (J. Industrial Microbiol., 24, 89-93 (2000)) have been reported.
However, such enzymatic processes using the enzyme itself require complicated steps such as a step of extracting an enzyme from plants or bacteria and preparation of an immobilized enzyme, and it has hence been desirable to develop a simpler process for producing G-1-P.
It is an object of the present invention to provide a process for producing G-1-P by which a mass of G-1-P can be provided without using complicated steps.
The present inventors have carried out various investigations as to bacteria producing a mass of G-1-P in a medium by culture. As a result, it has been found that when bacteria of the genus Corynebacterium are cultured under conditions of the presence of a saccharide and a high concentration of phosphoric acid or a derivative thereof, a high concentration of G-1-P can be produced directly in a medium to produce a mass of G-1-P.
According to the present invention, there is thus provided a process for producing glucose-1-phosphate, comprising the steps of culturing bacteria of the genus Corynebacterium in a medium containing a saccharide and at least 1 mM of phosphoric acid or a derivative or salt thereof, and collecting glucose-1-phosphate produced and accumulated in the medium.